1. Field of the Invention
The present invention relates to a mutant plant produced by inducing genetic recombination of genomic DNA, a method for producing a mutant plant, and a method of increasing the frequency of genetic recombination.
2. Background Art
There is a known method for obtaining a variety of mutants by artificially inducing genetic recombination of genomic DNA (JP Patent No. 4158920). According to this method, so-called “genomic shuffling” is artificially induced. Thus, a mutant having rearranged genomic DNA can be efficiently obtained.
The method described in JP Patent No. 4158920 is a method of increasing the frequency of genetic recombination by causing TaqI (a restriction enzyme that recognizes 4 nucleotides) to be expressed in target fungal cells, transiently activating TaqI through temperature control, and introducing at least two double strand breaks at arbitrary sites in genomic DNA. Fungal cells having improved genetic characteristics can be produced by this method.
Specifically, in the method disclosed in JP Patent No. 4158920, first, the TaqI gene is transformed into yeast with an auxotrophic marker. A transformed yeast is obtained based on auxotrophy. Next, the transformed yeast is retained for a certain time period at a temperature at which TaqI is activated (50° C.) such that TaqI is transiently activated. It has been shown that such temperature treatment causes increased frequency of genetic recombination.
In addition, JP Patent No. 4158920 teaches that the above method can be applied to plant cells (paragraph 0011). However, JP Patent No. 4158920 does not disclose the Example in which the method was actually applied to plant cells. Therefore, it is still unknown whether mutant plants can be produced by applying the method to plant cells.